Dual stapler

ABSTRACT

Two conventional wire staple cartridges are loaded in a stapler containing two staple drivers and a matching dual stapleclenching anvil. A mode selector allows selection between single staple operation is selected, a single manual motion drives and clinches two staples in a prescribed parallel pattern to securely fasten assembled sheets of material.

United States Patent [1 1 Kuypers l l June 17, 1975 l l DUAL STAPLER [76] Inventor: Ned Robert Kuypers, 432 Covington Rd., Los Altos. Calif. 94022 22 Filed: Dec.6.l973

211 App1.No.:422,57l

[52] U.S. Cl 227/109; 227/l20 [51] Int. Cl. B256 5/02 [58] Field of Search U 227/76, 109, I20

[56] References Cited UNITED STATES PATENTS 2.679.045 5/[954 Neumann 227/76 2,697,83l 12/1954 Neumann l27/l20 X 2,776,431 llll 6,538

Strong 227/]20 Oussuni 227/l09 X Primar E.\'aminer-(jranville Y. Custer, Jr, Attorney, Agent, or FirmRoland l Griffin [57} ABSTRACT Two conventional wire staple cartridges are loaded in a stapler containing two staple drivers and a matching dual staple-clenching anvil. A mode selector allows selection between single staple operation is selected, a single manual motion drives and clinches two staples in a prescribed parallel pattern to securely fasten assembled sheets of material.

15 Claims, 6 Drawing Figures PATENTEDJUN 1 7 a a 8 9.865

SHEET 3 F T--F o 0 CENTER OF F CENTER or ROTATION ROTATION SlNGLE STAPLE JOINT DUAL STAPLE JomT V Fig. 5

Fig.6%

DUAL STAPLER BACKGROUND OF THE INVENTION This invention relates to staplers for fastening paper sheets or other layered material using wire staples. Conventional desk-top hand-operated staplers all operate on the same basic principle, namely: a single motion of the hand (striking. pushing, or squeezing) drives a single wire staple through the material to be fastened and into a die or anvil that clinches the free ends of the staple and completes the joint. This method is usually adequate for temporary joints, but for material which is to be kept intact or handled and used repeatedly (cg. memoranda for circulation, copies of legal documents and records, file copy material, etc.) or any type of material for which a more permanent joint is desirable to prevent disorder or separation, a single wire staple joint is often inadequate.

A single wire staple joint provides little resistance to the relative rotation of one sheet of material with respect to another in their common plane of attachment as the two punctured holes in a given sheet of material readily enlarge due to the stresses produced by even moderate handling. A solution to this problem is to drive two wire staples through the sheets of material to be fastened in such a way as to increase the strength of the wire staple joint without inhibiting the useful handling of the sheets of material. However. with conventional staplers this requires two consecutive hand oper utions. Moreover, there is no provision for a predetermined location of the second wire staple with respect to the first. Thus. the wire staple joint produced may be disordered and ineffective.

SUMMARY OF THE INVENTION It is the principal object of this invention to provide a manually-operated stapler which, at the option of the user, can be used to drive either a single wire staple in the conventional manner or two wire staples in a prescribed parallel pattern with a single motion when a more permanent joint is desired.

This object is accomplished according to the preferred embodiment of this invention by providing a dual stapler in which two conventional wire staple cartridges are loaded on opposite sides of a center stop, the wire staples being driven manually by the user through the action of a dual driver assembly. The engagement of the dual driver assembly with the wire staple cartridges is determined by the position of a mode selector lever that enables the user to preselect between single and dual stapling modes.

Other and incidental objects of this invention will be apparent from a reading of this specification and an inspection of the accompanying drawings.

DESCRIPTION OF THE DRAWINGS FIG. I is a cut-a-way pictorial view of a dual stapler according to the preferred embodiment of this invention.

FIGS. 2, 3, and 4 are cut-a-way views of the charac teristic elements of the dual stapler of FIG. 1 illustrating the relative positions of these elements in the nonactuated or free state (FIG. 2), in the singly-actuated state with the mode selector lever having been preset in the single staple mode (FIG. 3), and in the dualactuated state with the mode selector lever having been preset in the dual staple mode (FIG. 4),

FIG. 5 illustrates the physical principles upon which the parallel staple pattern produced by the dual stapler of FIGS. 1-4 is based.

FIGv 6 is a cut-a-way pictorial view of an alternative dual driver and mode selector mechanism for a dual stapler of the type illustrated in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. I, a dual stapler according to the preferred embodiment of this invention comprises a mounting base I with an integrally attached dual staple clinching anvil 2; a staple magazine 3 with provi sion for two wire staple cartridges 4 and 5; two springloaded followers 6 that force the staple cartridges 4 and 5 against opposing sides of a center stop 7; a rigidly constrained staple driver 8; a variably constrained staple driver 9; and a cover I0 with an integrally attached two-position slider 11 and mode selector lever 12. The two drivers 8 and 9 are attached by a common fixed rivet 13 to the pivoted end of the cover I0. The variably constrained driver 9 is of a leaf spring design allowing free vertical movement relative to the rigidly constrained staple driver 8 unless constrained by the slider 11. The base I. staple magazine 3, and cover II) are attached by a common pivot pin 14 at the pivoted end thereof. The rear ends of the rigidly and variably constrained drivers 8 and 9 extend behind the pivot pin 14 to form a return spring 15 which acts against an upper rear portion I6 of the base I to return the cover 10 to the normal non-actuated or free position after actuation. A separate leaf spring 17 is also attached to the cover I0 by the common fixed rivet I3 and acts against the staple magazine 3 to separate the cover 10 from the staple magazine 3. Attached to the front end of the staple magazine 3 is a leaf spring 18 having an offset tip at its free end positioned so as to engage a mating protruding lip 19 of the cover 10.

Referring now to FIG. 2, a cross-sectional view of the dual stapler is shown illustrating the relative positions of the essential elements in the non-actuated or free position. To insert wire staple cartridges into the unloaded dual stapler the user simply pulls the cover 10 and the staple magazine 3 apart by exerting sufficient force to deflect the spring 18 and thereby release the cover 10 from the staple magazine 3. The cover 10 is then swung upward allowing insertion of the wire staple cartridges 4 and 5 (shown in place in FIG. 2) between their respective followers 6 and the center stop 7. The cover 10 is then swung down against the tip of spring 18. Squeezing the cover 10 and staple magazine 3 together again deflects the spring 18 and causes captive engagement of the protruding lip 19 of the cover 10 by the offset tip of spring 18. Once engaged, the retaining spring 18 moves freely within the cover 10 during actuation and only serves to limit the separation of the cover 10 and staple magazine 3 caused by the action of spring 17. The dual stapler is now ready for use.

To drive a single wire staple in the conventional manner, the user pushes the two-position slider 11 into position A using the attached mode selector lever I2. With the material 20 to be joined positioned above the dual staple-clinching anvil 2, the user drives the cover I0 downward by hand as shown in FIG. 3. This forces the rigidly constrained staple driver 8 through the rear wire staple cartridge 4 and drives the end wire staple 2| adjacent to the rear of the center stop 7 through a corresponding opening of the staple magazine 3. through the material 20. and into the rear cavity 22 of the dual staple-clinching anvil 2 which clinches the legs of the wire staple to complete the joint. The variably constrained staple driver 9 recedes freely up into the cover 10 upon contact viith the front wire staple cartridge 5 without driving a corresponding wire staple. Upon removal of the manual driving force the action of springs I5 and I7 returns the dual stapler to the non-actuated or free state shown in FIG. 2.

To drive two staples simultaneously the user pushes the two-position slider II into position 8 shown in FIG. 2, using the attached mode selector lever 12. This constrains the variably constrained driver 9 to move with the cover I0. With the material 20 to be joined pi sitioned above the dual staple'clinching anvil 2, the user drives the cover downward by hand as shown in FIG. 4. This forces the variably constrained staple driver 9 through the front wire staple cartridge 5 and drives the end wire staple 23 adjacent to the front of the center stop 7 through a corresponding opening of the staple magazine 3. through the material 20. and into the front cavity 24 of the dual staple-clinching anvil 2 while at the same time forcing the rigidly con strained staple driver 8 through the rear wire staple cartridge 4 to drive the end wire staple 21 adjacent to the rear of the center stop 7 through the corresponding opening of the staple magazine 3, through the material 20, and into the rear cavity 22 of the dual stapleclinching anvil 2. The legs of both wire staples 2] and 23 are thus clinched simultaneously to complete the dual wire staple joint. Upon removal of the manual driving force the action of springs and 17 returns the dual stapler to the non-actuated or free state shown in FIG. 2.

Referring again to FIG. 2, it will be noted that due to the inherent geometry of the dual stapler the distance between the pivot pin 14 and the location at which the actuation force 25 is applied can be made approxi mately equal to twice the distance between the pivot pin 14 and the center stop 7 thereby providing an operating mechanical advantage of approximately twoto-one. As a result. the force required to drive two wire staples simultaneously using the dual stapler is no greater than that required to drive a single wire staple using a conventional stapler in which the actuation force is applied directly above the wire staple to be driven. Likewise the force required to drive a single wire staple using the dual stapler is approximately one half that required to drive a single wire staple using a conventional stapler.

The dual stapler provides yet another degree of utility in that when used for single staple operation. as shown in FIG. 3, the wire staple cartridge 5 serves as a reserve staple cartridge permitting uninterrupted use of the dual stapler for single staple operation after the wire staple cartridge 4 is exhausted. Once the wire staple cartridge 4 is exhausted, the user need only move selector lever 12 from position A, as shown in FIG. 3, to position 8, as shown in FIG. 4, to allow continued single staple operation without requiring immediate cartridge reloading.

The force geometry of a conventional single wire staple joint, such as that produced when the dual stapler is operated in the single stapling mode, and of the dual wire staple joint produced when the dual stapler is operated in the dual stapling mode is shown in FIG. 5

where X is defined as the fixed distance between the two legs of each wire staple; Y is defined as the spacing between the two wire staples of the dual wire staple joint; and F is defined as the maximum resisting force that can be exerted by a sheet of material against the leg of a wire staple, when sheets are subjected to relative rotation in their common plane of attachment. without yielding to failure by tearing (F is a constant for a given material). The maximum resisting moment M (defined as the moment of the maximum resisting force couple produced at failure for the particular joint illustrated) that can be produced by the single wire sta ple joint is just equal to the product of the force F and the distance X (i.e. M=FX). On the other hand. the maximum resisting moment M that can be producedby the dual wire staple joint is equal to twice the roduct of the force F and the distance X -l-l (i.e. M=2F X H It follows that for the dual wire staple joint M 2FX for all Y O. Therefore, in addition to the obvious increased resistance to direct separation of material. the dual wire staple joint produced by the dual stapler provides more than twice the resistance to failure due to rotation of one sheet with respect to another in their common plane of attachment than that provided by the conventional single wire staple joint. Referring now to FIG. 6, there is shown an alternative dual driver and mode selector mechanism that may be employed in the dual stapler of FIGS. 1-4. This mechanism include a pair of staple drivers 26 and 27 fixed with respect to each other and the cover 28 and driven simultaneously upon actuation of the dual stapler. For single staple operation one slides the twoposition slider 29, which is positioned within a recessed portion of the center stop 30 and retained within two slots 31 (one on each side of the staple magazine 32), against the staple cartridge 33, against the corresponding force produced by the spring-loaded follower 34, and into two captivating slots 35 (one on each side of the staple magazine 32). This removes the staple cartridge 33 from its original position against the center stop 30. Thus, subsequent actuation of the dual stapler causes only the end staple 36 of the cartridge 37 to be driven by the staple driver 27. Releasing the twoposition slider 29 from the captivating slots 35 allows the staple cartridge 33 to be returned to its original position against the center stop 30 due to the action of the spring-loaded follower 34. Subsequent actuation of the dual stapler causes the two end staples 36 and 38 to be driven by the staple drivers 27 and 26 in the prescribed parallel dual staple pattern.

I claim: 1. A dual stapler comprising: common supply means for simultaneously holding two cartridges of wire staples and feeding those cartridges along a common axis of the supply means to a pair of driving locations of the supply means to define a prescribed dual staple pattern; dual anvil means mounted adjacent to the supply means for clinching two wire staples driven thereagainst from the driving locations of the supply means; dual driver means mounted adjacent to the supply means for driving a pair of wire staples positioned at the driving locations of the supply means in the prescribed dual staple pattern against the dual anvil means to form a dual staple joint; and

actuator means for receiving an actuation force to actuate the dual driver means.

2. A dual stapler as in claim 1 wherein said dual driver means simultaneously drives a pair of wire staples positioned at the driving locations of the supply means in the same direction and in the prescribed dual staple pattern against the dual anvil means to form a dual staple joint in response to a single operation of the actuator means.

3. A dual stapler as in claim 2 wherein:

said supply means includes a common center stop;

said driving locations are positioned in spaced parallel relationship along the common axis of the supply means and on opposite sides of the center stop; and

said supply means feeds the cartridges of wire staples in opposite directions along the common axis of the supply means to the driving locations positioned on opposite sides of the center stop.

4. A dual stapler as in claim 3 including selecting means for selecting between single staple operation and dual staple operation.

5. A dual stapler as in claim 4 wherein said dual driver means includes:

a first driver fixed at one end and rigidly constrained at the other end for driving a wire staple positioned at one of the driving locations; and

a second driver in a leaf spring configuration fixed at one end and variably constrained at the other end for selectively driving a wire staple positioned at the other of the driving locations.

6. A dual stapler as in claim 5 wherein said selecting means comprises a movable two-position slider operable in one position for rigidly constraining said other end of the second driver so as to drive a wire staple upon operation of the actuator means and operable in the other position for allowing free motion of said other end of the second driver so as not to drive a wire staple upon operation of the actuator means.

7. A dual stapler as in claim 6 wherein said twoposition slider can be moved to said one position to allow continued single staple operation of the dual stapler after the cartridge of wire staples fed to said one of the driving locations has been exhausted.

8. A dual stapler as in claim 1 wherein:

said actuator means, said common supply means, and a base including said dual anvil means are attached by a common pivot pin and separated by spring members; and

the actuation force may be applied to the actuator means at a point twice the distance from the pivot pin to the staple driving locations of the supply means to provide a mechanical advantage of twoto-one and thereby reduce the actuation force required to operate the dual stapler.

9. A dual stapler as in claim 1 including selecting means for selecting between single staple operation and dual staple operation.

10. A dual stapler as in claim 9 wherein: said dual driver means includes a pair of drivers each fixed at one end and operable at the other end for driving a wire staple at a corresponding one of the driving locations; and

said selecting means comprises a movable twoposition slider operable in one position for rigidly constraining a free end of one of said drivers so as to drive a wire staple upon operation of the actuator means and operable in the other position for allowing free motion of the free end of said one of the drivers so as not to drive a wire staple upon op eration of the actuator means.

11. A dual stapler as in claim 2 wherein said dual driver means includes two staple drivers fixed with re spect to one another for driving a pair of staples at the driving locations.

12. A dual stapler as in claim 11 including selecting means for selecting between single staple operation and dual staple operation, said selecting means comprising a movable two-position slider operable in one position for permitting one of the cartridges of wire staples to be fed to a corresponding one of the driving locations of the supply means and operable in the other position for preventing said one ofthe cartridges from being fed to said one of the driving locations.

13. A dual stapler as in claim 12 wherein said two position slider can be moved to said one position to allow continued single staple operation of the dual stapler after the other of the cartridges of wire staples fed to the other of the driving locations has been ex hausted.

14. A dual stapler comprising:

supply means for simultaneously holding two cartridges of wire staples and feeding them to a pair of driving locations of the supply means to define a prescribed dual staple pattern;

dual anvil means mounted adjacent to the supply means for clinching two wire staples driven thereagainst rom the driving locations of the supply means, said dual anvil means comprising two staple-clinching cavities positioned in spaced parallel relationship along a common axis and oriented orthogonal to the common axis;

dual driver means mounted adjacent to the supply means for driving a pair of wire staples positioned at the driving locations of the supply means in the same direction and in the prescribed dual staple pattern against the dual anvil means to form a dual staple joint; and

actuator means for receiving an actuation force to actuate the dual driver means.

15. A dual stapler as in claim 14 including selecting means for selecting between single staple operation and dual staple operation.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 3,: 5J,Q65 D d June 17, 1975 Inventor(s) Ned Robert r'iuygers It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On tne title gage, section [57], in the third line of the PBS'IRACT, change "clenching" to clinching-; and

On the title page, section [57], in the tourtn line of the ABSTRACT, between "ooeration" and "is" insert and dual sta gle ogeration. amen dual sta gle o;neration.

Signed and Salad this twenty-eight Day of October 1975 [SEAL] Attest:

RUTH C. MASON C. MARSHALL DANN .4 [testing Officer (ummissimwr of Parents and Trademarks 

1. A dual stapler comprising: common supply means for simultaneously holding two cartridges of wire staples and feeding those cartridges along a common axis of the supply means to a pair of driving locations of the supply means to define a prescribed dual staple pattern; dual anvil means mounted adjacent to the supply means for clinching two wire staples driven thereagainst from the driving locations of the supply means; dual driver means mounted adjacent to the supply means for driving a pair of wire staples positioned at the driving locations of the supply means in the prescribed dual staple pattern against the dual anvil means to form a dual staple joint; and actuator means for receiving an actuation force to actuate the dual driver means.
 2. A dual stapler as in claim 1 wherein said dual driver means simultaneously drives a pair of wire staples positioned at the driving locations of the supply means in the same direction and in the prescribed dual staple pattern against the dual anvil means to form a dual staple joint in response to a single operation of the actuator means.
 3. A dual stapler as in claim 2 wherein: said supply means includes a common center stop; said driving locations are positioned in spaced parallel relationship along the common axis of the supply means and on opposite sides of the center stop; and said supply means feeds the cartridges of wire staples in opposite directions along the common axis of the supply means to the driving locations positioned on opposite sides of the center stop.
 4. A dual stapler as in claim 3 including selecting means for selecting between single staple operation and dual staple operation.
 5. A dual stapler as in claim 4 wherein said dual driver means includes: a first driver fixed at one end and rigidly constrained at the other end for driving a wire staple positioned at one of the driving locations; and a second driver in a leaf spring configuration fixed at one end and variably constrained at the other end for selectively driving a wire staple positioned at the other of the driving locations.
 6. A dual stapler as in claim 5 wherein said selEcting means comprises a movable two-position slider operable in one position for rigidly constraining said other end of the second driver so as to drive a wire staple upon operation of the actuator means and operable in the other position for allowing free motion of said other end of the second driver so as not to drive a wire staple upon operation of the actuator means.
 7. A dual stapler as in claim 6 wherein said two-position slider can be moved to said one position to allow continued single staple operation of the dual stapler after the cartridge of wire staples fed to said one of the driving locations has been exhausted.
 8. A dual stapler as in claim 1 wherein: said actuator means, said common supply means, and a base including said dual anvil means are attached by a common pivot pin and separated by spring members; and the actuation force may be applied to the actuator means at a point twice the distance from the pivot pin to the staple driving locations of the supply means to provide a mechanical advantage of two-to-one and thereby reduce the actuation force required to operate the dual stapler.
 9. A dual stapler as in claim 1 including selecting means for selecting between single staple operation and dual staple operation.
 10. A dual stapler as in claim 9 wherein: said dual driver means includes a pair of drivers each fixed at one end and operable at the other end for driving a wire staple at a corresponding one of the driving locations; and said selecting means comprises a movable two-position slider operable in one position for rigidly constraining a free end of one of said drivers so as to drive a wire staple upon operation of the actuator means and operable in the other position for allowing free motion of the free end of said one of the drivers so as not to drive a wire staple upon operation of the actuator means.
 11. A dual stapler as in claim 2 wherein said dual driver means includes two staple drivers fixed with respect to one another for driving a pair of staples at the driving locations.
 12. A dual stapler as in claim 11 including selecting means for selecting between single staple operation and dual staple operation, said selecting means comprising a movable two-position slider operable in one position for permitting one of the cartridges of wire staples to be fed to a corresponding one of the driving locations of the supply means and operable in the other position for preventing said one of the cartridges from being fed to said one of the driving locations.
 13. A dual stapler as in claim 12 wherein said two-position slider can be moved to said one position to allow continued single staple operation of the dual stapler after the other of the cartridges of wire staples fed to the other of the driving locations has been exhausted.
 14. A dual stapler comprising: supply means for simultaneously holding two cartridges of wire staples and feeding them to a pair of driving locations of the supply means to define a prescribed dual staple pattern; dual anvil means mounted adjacent to the supply means for clinching two wire staples driven thereagainst from the driving locations of the supply means, said dual anvil means comprising two staple-clinching cavities positioned in spaced parallel relationship along a common axis and oriented orthogonal to the common axis; dual driver means mounted adjacent to the supply means for driving a pair of wire staples positioned at the driving locations of the supply means in the same direction and in the prescribed dual staple pattern against the dual anvil means to form a dual staple joint; and actuator means for receiving an actuation force to actuate the dual driver means.
 15. A dual stapler as in claim 14 including selecting means for selecting between single staple operation and dual staple operation. 